Retire Material Composer

[hmans]

Extracting what used to be known as VFXMaterial into a separate library felt like a good idea at the time, but it's created two problems:

• It is now very hard to explain to users when they should be using Shader Composer, when Material Composer, and when VFX Composer, especially since each one requires the ones before it (with VFX Composer, you'll work with all three, and have to add all three to your project even for very basic effects, ouch)
• The only thing that VFX Composer implements now is the particles engine. Why would the library still be called VFX Composer, especially considering a lot of VFX don't even use particles?

For this reason, I want to re-integrate the functionality that Material Composer provides back into VFX Composer. I'm using the opportunity to implement a new style of JSX API for module composition that sits on top of Shader Composer's new <Shader> construct that will be a lot more lightweight and frictionless than the current Composable.* and Modules.* proxies:

<meshStandardMaterial>
  <ShaderModules>
    <Color ... />
    <Velocity ... />
    {/* etc. *}
  </ShaderModules>
</meshStandardMaterial>

The good news is that this will not break existing code, or otherwise invalidate Material Composer; you will still be able to use it to create materials, but the library will be deprecated in favor of VFX Composer's new material composition API.

Details to follow when I get started with implementing this.